1. Technical Field
The present invention relates to the field of antennas, and more particularly, to systems for rapidly steering antennas having directive beams.
2. Discussion of Related Art
Two main technologies are known in the art for implementing a telecommunication antenna (such as Satellite Communication—SATCOM) on a mobile platform (such as an Unmanned Arial Vehicles—UAVs). Such an antenna needs to address both short and fast movements as well as long and relatively slow movements.
One known technology is a mechanically steered antenna. An antenna (e.g.—a parabolic dish) is mounted on a motorized 3 axis gimbals. The motors are controlled to implement the fast and slow movements of the dish.
Another technology is phased array in which the antenna comprises of a large number of small—i.e.—Omni directional—radiating elements, the phase and sometime amplitude of the signals of each element is controlled so that the signals going through all the elements combine in space to create a beam pointing in the desired direction.
Fast beam movements of a mechanically steered antenna, even if the motions are small, requires large mechanical moments which means sturdy motors and mechanics, large currents and high power electronics.
Phased arrays do not require all of these but have other drawbacks—their directivity is severely degraded when the beam is steered far away from the bore sight of the array and implementing a large aperture antenna requires a very large number of radiating elements and the associated electronics becomes very complex, expensive, power consuming and hot.